Re-enable hoedown by default

7 files changed, 382 insertions, 150 deletions

diff --git a/src/librustdoc/html/markdown.rs b/src/librustdoc/html/markdown.rs
index 4bf856240f6..614d59c512d 100644
--- a/src/librustdoc/html/markdown.rs
+++ b/src/librustdoc/html/markdown.rs
@@ -32,6 +32,7 @@ use std::ascii::AsciiExt;
 use std::cell::RefCell;
 use std::collections::{HashMap, VecDeque};
 use std::default::Default;
+use std::ffi::CString;
 use std::fmt::{self, Write};
 use std::str;
 use syntax::feature_gate::UnstableFeatures;
@@ -40,21 +41,28 @@ use syntax::codemap::Span;
 use html::render::derive_id;
 use html::toc::TocBuilder;
 use html::highlight;
+use html::escape::Escape;
 use test;
 
 use pulldown_cmark::{html, Event, Tag, Parser};
 use pulldown_cmark::{Options, OPTION_ENABLE_FOOTNOTES, OPTION_ENABLE_TABLES};
 
+#[derive(PartialEq, Debug, Clone, Copy)]
+pub enum RenderType {
+    Hoedown,
+    Pulldown,
+}
+
 /// A unit struct which has the `fmt::Display` trait implemented. When
 /// formatted, this struct will emit the HTML corresponding to the rendered
 /// version of the contained markdown string.
 // The second parameter is whether we need a shorter version or not.
-pub struct Markdown<'a>(pub &'a str);
+pub struct Markdown<'a>(pub &'a str, pub RenderType);
 /// A unit struct like `Markdown`, that renders the markdown with a
 /// table of contents.
-pub struct MarkdownWithToc<'a>(pub &'a str);
+pub struct MarkdownWithToc<'a>(pub &'a str, pub RenderType);
 /// A unit struct like `Markdown`, that renders the markdown escaping HTML tags.
-pub struct MarkdownHtml<'a>(pub &'a str);
+pub struct MarkdownHtml<'a>(pub &'a str, pub RenderType);
 /// A unit struct like `Markdown`, that renders only the first paragraph.
 pub struct MarkdownSummaryLine<'a>(pub &'a str);
 
@@ -73,6 +81,14 @@ fn stripped_filtered_line<'a>(s: &'a str) -> Option<&'a str> {
     }
 }
 
+/// Returns a new string with all consecutive whitespace collapsed into
+/// single spaces.
+///
+/// Any leading or trailing whitespace will be trimmed.
+fn collapse_whitespace(s: &str) -> String {
+    s.split_whitespace().collect::<Vec<_>>().join(" ")
+}
+
 /// Convert chars from a title for an id.
 ///
 /// "Hello, world!" -> "hello-world"
@@ -368,6 +384,7 @@ const HOEDOWN_EXT_AUTOLINK: libc::c_uint = 1 << 3;
 const HOEDOWN_EXT_STRIKETHROUGH: libc::c_uint = 1 << 4;
 const HOEDOWN_EXT_SUPERSCRIPT: libc::c_uint = 1 << 8;
 const HOEDOWN_EXT_FOOTNOTES: libc::c_uint = 1 << 2;
+const HOEDOWN_HTML_ESCAPE: libc::c_uint = 1 << 1;
 
 const HOEDOWN_EXTENSIONS: libc::c_uint =
     HOEDOWN_EXT_NO_INTRA_EMPHASIS | HOEDOWN_EXT_TABLES |
@@ -462,6 +479,13 @@ struct hoedown_buffer {
     unit: libc::size_t,
 }
 
+struct MyOpaque {
+    dfltblk: extern "C" fn(*mut hoedown_buffer, *const hoedown_buffer,
+                           *const hoedown_buffer, *const hoedown_renderer_data,
+                           libc::size_t),
+    toc_builder: Option<TocBuilder>,
+}
+
 extern {
     fn hoedown_html_renderer_new(render_flags: libc::c_uint,
                                  nesting_level: libc::c_int)
@@ -478,6 +502,7 @@ extern {
     fn hoedown_document_free(md: *mut hoedown_document);
 
     fn hoedown_buffer_new(unit: libc::size_t) -> *mut hoedown_buffer;
+    fn hoedown_buffer_puts(b: *mut hoedown_buffer, c: *const libc::c_char);
     fn hoedown_buffer_free(b: *mut hoedown_buffer);
 }
 
@@ -487,6 +512,208 @@ impl hoedown_buffer {
     }
 }
 
+pub fn render(w: &mut fmt::Formatter,
+              s: &str,
+              print_toc: bool,
+              html_flags: libc::c_uint) -> fmt::Result {
+    extern fn block(ob: *mut hoedown_buffer, orig_text: *const hoedown_buffer,
+                    lang: *const hoedown_buffer, data: *const hoedown_renderer_data,
+                    line: libc::size_t) {
+        unsafe {
+            if orig_text.is_null() { return }
+
+            let opaque = (*data).opaque as *mut hoedown_html_renderer_state;
+            let my_opaque: &MyOpaque = &*((*opaque).opaque as *const MyOpaque);
+            let text = (*orig_text).as_bytes();
+            let origtext = str::from_utf8(text).unwrap();
+            let origtext = origtext.trim_left();
+            debug!("docblock: ==============\n{:?}\n=======", text);
+            let rendered = if lang.is_null() || origtext.is_empty() {
+                false
+            } else {
+                let rlang = (*lang).as_bytes();
+                let rlang = str::from_utf8(rlang).unwrap();
+                if !LangString::parse(rlang).rust {
+                    (my_opaque.dfltblk)(ob, orig_text, lang,
+                                        opaque as *const hoedown_renderer_data,
+                                        line);
+                    true
+                } else {
+                    false
+                }
+            };
+
+            let lines = origtext.lines().filter(|l| {
+                stripped_filtered_line(*l).is_none()
+            });
+            let text = lines.collect::<Vec<&str>>().join("\n");
+            if rendered { return }
+            PLAYGROUND.with(|play| {
+                // insert newline to clearly separate it from the
+                // previous block so we can shorten the html output
+                let mut s = String::from("\n");
+                let playground_button = play.borrow().as_ref().and_then(|&(ref krate, ref url)| {
+                    if url.is_empty() {
+                        return None;
+                    }
+                    let test = origtext.lines().map(|l| {
+                        stripped_filtered_line(l).unwrap_or(l)
+                    }).collect::<Vec<&str>>().join("\n");
+                    let krate = krate.as_ref().map(|s| &**s);
+                    let test = test::maketest(&test, krate, false,
+                                              &Default::default());
+                    let channel = if test.contains("#![feature(") {
+                        "&amp;version=nightly"
+                    } else {
+                        ""
+                    };
+                    // These characters don't need to be escaped in a URI.
+                    // FIXME: use a library function for percent encoding.
+                    fn dont_escape(c: u8) -> bool {
+                        (b'a' <= c && c <= b'z') ||
+                        (b'A' <= c && c <= b'Z') ||
+                        (b'0' <= c && c <= b'9') ||
+                        c == b'-' || c == b'_' || c == b'.' ||
+                        c == b'~' || c == b'!' || c == b'\'' ||
+                        c == b'(' || c == b')' || c == b'*'
+                    }
+                    let mut test_escaped = String::new();
+                    for b in test.bytes() {
+                        if dont_escape(b) {
+                            test_escaped.push(char::from(b));
+                        } else {
+                            write!(test_escaped, "%{:02X}", b).unwrap();
+                        }
+                    }
+                    Some(format!(
+                        r#"<a class="test-arrow" target="_blank" href="{}?code={}{}">Run</a>"#,
+                        url, test_escaped, channel
+                    ))
+                });
+                s.push_str(&highlight::render_with_highlighting(
+                               &text,
+                               Some("rust-example-rendered"),
+                               None,
+                               playground_button.as_ref().map(String::as_str)));
+                let output = CString::new(s).unwrap();
+                hoedown_buffer_puts(ob, output.as_ptr());
+            })
+        }
+    }
+
+    extern fn header(ob: *mut hoedown_buffer, text: *const hoedown_buffer,
+                     level: libc::c_int, data: *const hoedown_renderer_data,
+                     _: libc::size_t) {
+        // hoedown does this, we may as well too
+        unsafe { hoedown_buffer_puts(ob, "\n\0".as_ptr() as *const _); }
+
+        // Extract the text provided
+        let s = if text.is_null() {
+            "".to_owned()
+        } else {
+            let s = unsafe { (*text).as_bytes() };
+            str::from_utf8(&s).unwrap().to_owned()
+        };
+
+        // Discard '<em>', '<code>' tags and some escaped characters,
+        // transform the contents of the header into a hyphenated string
+        // without non-alphanumeric characters other than '-' and '_'.
+        //
+        // This is a terrible hack working around how hoedown gives us rendered
+        // html for text rather than the raw text.
+        let mut id = s.clone();
+        let repl_sub = vec!["<em>", "</em>", "<code>", "</code>",
+                            "<strong>", "</strong>",
+                            "&lt;", "&gt;", "&amp;", "&#39;", "&quot;"];
+        for sub in repl_sub {
+            id = id.replace(sub, "");
+        }
+        let id = id.chars().filter_map(|c| {
+            if c.is_alphanumeric() || c == '-' || c == '_' {
+                if c.is_ascii() {
+                    Some(c.to_ascii_lowercase())
+                } else {
+                    Some(c)
+                }
+            } else if c.is_whitespace() && c.is_ascii() {
+                Some('-')
+            } else {
+                None
+            }
+        }).collect::<String>();
+
+        let opaque = unsafe { (*data).opaque as *mut hoedown_html_renderer_state };
+        let opaque = unsafe { &mut *((*opaque).opaque as *mut MyOpaque) };
+
+        let id = derive_id(id);
+
+        let sec = opaque.toc_builder.as_mut().map_or("".to_owned(), |builder| {
+            format!("{} ", builder.push(level as u32, s.clone(), id.clone()))
+        });
+
+        // Render the HTML
+        let text = format!("<h{lvl} id='{id}' class='section-header'>\
+                           <a href='#{id}'>{sec}{}</a></h{lvl}>",
+                           s, lvl = level, id = id, sec = sec);
+
+        let text = CString::new(text).unwrap();
+        unsafe { hoedown_buffer_puts(ob, text.as_ptr()) }
+    }
+
+    extern fn codespan(
+        ob: *mut hoedown_buffer,
+        text: *const hoedown_buffer,
+        _: *const hoedown_renderer_data,
+        _: libc::size_t
+    ) -> libc::c_int {
+        let content = if text.is_null() {
+            "".to_owned()
+        } else {
+            let bytes = unsafe { (*text).as_bytes() };
+            let s = str::from_utf8(bytes).unwrap();
+            collapse_whitespace(s)
+        };
+
+        let content = format!("<code>{}</code>", Escape(&content));
+        let element = CString::new(content).unwrap();
+        unsafe { hoedown_buffer_puts(ob, element.as_ptr()); }
+        // Return anything except 0, which would mean "also print the code span verbatim".
+        1
+    }
+
+    unsafe {
+        let ob = hoedown_buffer_new(DEF_OUNIT);
+        let renderer = hoedown_html_renderer_new(html_flags, 0);
+        let mut opaque = MyOpaque {
+            dfltblk: (*renderer).blockcode.unwrap(),
+            toc_builder: if print_toc {Some(TocBuilder::new())} else {None}
+        };
+        (*((*renderer).opaque as *mut hoedown_html_renderer_state)).opaque
+                = &mut opaque as *mut _ as *mut libc::c_void;
+        (*renderer).blockcode = Some(block);
+        (*renderer).header = Some(header);
+        (*renderer).codespan = Some(codespan);
+
+        let document = hoedown_document_new(renderer, HOEDOWN_EXTENSIONS, 16);
+        hoedown_document_render(document, ob, s.as_ptr(),
+                                s.len() as libc::size_t);
+        hoedown_document_free(document);
+
+        hoedown_html_renderer_free(renderer);
+
+        let mut ret = opaque.toc_builder.map_or(Ok(()), |builder| {
+            write!(w, "<nav id=\"TOC\">{}</nav>", builder.into_toc())
+        });
+
+        if ret.is_ok() {
+            let buf = (*ob).as_bytes();
+            ret = w.write_str(str::from_utf8(buf).unwrap());
+        }
+        hoedown_buffer_free(ob);
+        ret
+    }
+}
+
 pub fn old_find_testable_code(doc: &str, tests: &mut ::test::Collector, position: Span) {
     extern fn block(_ob: *mut hoedown_buffer,
                     text: *const hoedown_buffer,
@@ -511,7 +738,22 @@ pub fn old_find_testable_code(doc: &str, tests: &mut ::test::Collector, position
                 stripped_filtered_line(l).unwrap_or(l)
             });
             let filename = tests.get_filename();
-            tests.add_old_test(lines.collect::<Vec<&str>>().join("\n"), filename);
+
+            if tests.render_type == RenderType::Hoedown {
+                let text = (*text).as_bytes();
+                let text = str::from_utf8(text).unwrap();
+                let lines = text.lines().map(|l| {
+                    stripped_filtered_line(l).unwrap_or(l)
+                });
+                let text = lines.collect::<Vec<&str>>().join("\n");
+                tests.add_test(text.to_owned(),
+                               block_info.should_panic, block_info.no_run,
+                               block_info.ignore, block_info.test_harness,
+                               block_info.compile_fail, block_info.error_codes,
+                               line, filename);
+            } else {
+                tests.add_old_test(lines.collect::<Vec<&str>>().join("\n"), filename);
+            }
         }
     }
 
@@ -533,7 +775,6 @@ pub fn old_find_testable_code(doc: &str, tests: &mut ::test::Collector, position
     }
 
     tests.set_position(position);
-
     unsafe {
         let ob = hoedown_buffer_new(DEF_OUNIT);
         let renderer = hoedown_html_renderer_new(0, 0);
@@ -702,72 +943,84 @@ impl LangString {
 
 impl<'a> fmt::Display for Markdown<'a> {
     fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
-        let Markdown(md) = *self;
+        let Markdown(md, render_type) = *self;
+
         // This is actually common enough to special-case
         if md.is_empty() { return Ok(()) }
+        if render_type == RenderType::Hoedown {
+            render(fmt, md, false, 0)
+        } else {
+            let mut opts = Options::empty();
+            opts.insert(OPTION_ENABLE_TABLES);
+            opts.insert(OPTION_ENABLE_FOOTNOTES);
 
-        let mut opts = Options::empty();
-        opts.insert(OPTION_ENABLE_TABLES);
-        opts.insert(OPTION_ENABLE_FOOTNOTES);
-
-        let p = Parser::new_ext(md, opts);
+            let p = Parser::new_ext(md, opts);
 
-        let mut s = String::with_capacity(md.len() * 3 / 2);
+            let mut s = String::with_capacity(md.len() * 3 / 2);
 
-        html::push_html(&mut s,
-                        Footnotes::new(CodeBlocks::new(HeadingLinks::new(p, None))));
+            html::push_html(&mut s,
+                            Footnotes::new(CodeBlocks::new(HeadingLinks::new(p, None))));
 
-        fmt.write_str(&s)
+            fmt.write_str(&s)
+        }
     }
 }
 
 impl<'a> fmt::Display for MarkdownWithToc<'a> {
     fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
-        let MarkdownWithToc(md) = *self;
+        let MarkdownWithToc(md, render_type) = *self;
 
-        let mut opts = Options::empty();
-        opts.insert(OPTION_ENABLE_TABLES);
-        opts.insert(OPTION_ENABLE_FOOTNOTES);
+        if render_type == RenderType::Hoedown {
+            render(fmt, md, true, 0)
+        } else {
+            let mut opts = Options::empty();
+            opts.insert(OPTION_ENABLE_TABLES);
+            opts.insert(OPTION_ENABLE_FOOTNOTES);
 
-        let p = Parser::new_ext(md, opts);
+            let p = Parser::new_ext(md, opts);
 
-        let mut s = String::with_capacity(md.len() * 3 / 2);
+            let mut s = String::with_capacity(md.len() * 3 / 2);
 
-        let mut toc = TocBuilder::new();
+            let mut toc = TocBuilder::new();
 
-        html::push_html(&mut s,
-                        Footnotes::new(CodeBlocks::new(HeadingLinks::new(p, Some(&mut toc)))));
+            html::push_html(&mut s,
+                            Footnotes::new(CodeBlocks::new(HeadingLinks::new(p, Some(&mut toc)))));
 
-        write!(fmt, "<nav id=\"TOC\">{}</nav>", toc.into_toc())?;
+            write!(fmt, "<nav id=\"TOC\">{}</nav>", toc.into_toc())?;
 
-        fmt.write_str(&s)
+            fmt.write_str(&s)
+        }
     }
 }
 
 impl<'a> fmt::Display for MarkdownHtml<'a> {
     fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
-        let MarkdownHtml(md) = *self;
+        let MarkdownHtml(md, render_type) = *self;
+
         // This is actually common enough to special-case
         if md.is_empty() { return Ok(()) }
+        if render_type == RenderType::Hoedown {
+            render(fmt, md, false, HOEDOWN_HTML_ESCAPE)
+        } else {
+            let mut opts = Options::empty();
+            opts.insert(OPTION_ENABLE_TABLES);
+            opts.insert(OPTION_ENABLE_FOOTNOTES);
 
-        let mut opts = Options::empty();
-        opts.insert(OPTION_ENABLE_TABLES);
-        opts.insert(OPTION_ENABLE_FOOTNOTES);
-
-        let p = Parser::new_ext(md, opts);
+            let p = Parser::new_ext(md, opts);
 
-        // Treat inline HTML as plain text.
-        let p = p.map(|event| match event {
-            Event::Html(text) | Event::InlineHtml(text) => Event::Text(text),
-            _ => event
-        });
+            // Treat inline HTML as plain text.
+            let p = p.map(|event| match event {
+                Event::Html(text) | Event::InlineHtml(text) => Event::Text(text),
+                _ => event
+            });
 
-        let mut s = String::with_capacity(md.len() * 3 / 2);
+            let mut s = String::with_capacity(md.len() * 3 / 2);
 
-        html::push_html(&mut s,
-                        Footnotes::new(CodeBlocks::new(HeadingLinks::new(p, None))));
+            html::push_html(&mut s,
+                            Footnotes::new(CodeBlocks::new(HeadingLinks::new(p, None))));
 
-        fmt.write_str(&s)
+            fmt.write_str(&s)
+        }
     }
 }
 
diff --git a/src/librustdoc/html/render.rs b/src/librustdoc/html/render.rs
index d55a0640562..57d71e6c4e0 100644
--- a/src/librustdoc/html/render.rs
+++ b/src/librustdoc/html/render.rs
@@ -72,7 +72,7 @@ use html::format::{TyParamBounds, WhereClause, href, AbiSpace};
 use html::format::{VisSpace, Method, UnsafetySpace, MutableSpace};
 use html::format::fmt_impl_for_trait_page;
 use html::item_type::ItemType;
-use html::markdown::{self, Markdown, MarkdownHtml, MarkdownSummaryLine};
+use html::markdown::{self, Markdown, MarkdownHtml, MarkdownSummaryLine, RenderType};
 use html::{highlight, layout};
 
 /// A pair of name and its optional document.
@@ -98,6 +98,7 @@ pub struct Context {
     /// publicly reused items to redirect to the right location.
     pub render_redirect_pages: bool,
     pub shared: Arc<SharedContext>,
+    pub render_type: RenderType,
 }
 
 pub struct SharedContext {
@@ -433,7 +434,8 @@ pub fn run(mut krate: clean::Crate,
            dst: PathBuf,
            passes: FxHashSet<String>,
            css_file_extension: Option<PathBuf>,
-           renderinfo: RenderInfo) -> Result<(), Error> {
+           renderinfo: RenderInfo,
+           render_type: RenderType) -> Result<(), Error> {
     let src_root = match krate.src.parent() {
         Some(p) => p.to_path_buf(),
         None => PathBuf::new(),
@@ -495,6 +497,7 @@ pub fn run(mut krate: clean::Crate,
         dst: dst,
         render_redirect_pages: false,
         shared: Arc::new(scx),
+        render_type: render_type,
     };
 
     // Crawl the crate to build various caches used for the output
@@ -1638,11 +1641,12 @@ fn plain_summary_line(s: Option<&str>) -> String {
 
 fn document(w: &mut fmt::Formatter, cx: &Context, item: &clean::Item) -> fmt::Result {
     document_stability(w, cx, item)?;
-    document_full(w, item)?;
+    document_full(w, item, cx.render_type)?;
     Ok(())
 }
 
-fn document_short(w: &mut fmt::Formatter, item: &clean::Item, link: AssocItemLink) -> fmt::Result {
+fn document_short(w: &mut fmt::Formatter, item: &clean::Item, link: AssocItemLink,
+                  render_type: RenderType) -> fmt::Result {
     if let Some(s) = item.doc_value() {
         let markdown = if s.contains('\n') {
             format!("{} [Read more]({})",
@@ -1651,7 +1655,7 @@ fn document_short(w: &mut fmt::Formatter, item: &clean::Item, link: AssocItemLin
             format!("{}", &plain_summary_line(Some(s)))
         };
         write!(w, "<div class='docblock'>{}</div>",
-               Markdown(&markdown))?;
+               Markdown(&markdown, render_type))?;
     }
     Ok(())
 }
@@ -1681,10 +1685,11 @@ fn get_doc_value(item: &clean::Item) -> Option<&str> {
     }
 }
 
-fn document_full(w: &mut fmt::Formatter, item: &clean::Item) -> fmt::Result {
+fn document_full(w: &mut fmt::Formatter, item: &clean::Item,
+                 render_type: RenderType) -> fmt::Result {
     if let Some(s) = get_doc_value(item) {
         write!(w, "<div class='docblock'>{}</div>",
-               Markdown(&format!("{}{}", md_render_assoc_item(item), s)))?;
+               Markdown(&format!("{}{}", md_render_assoc_item(item), s), render_type))?;
     }
     Ok(())
 }
@@ -1872,7 +1877,13 @@ fn item_module(w: &mut fmt::Formatter, cx: &Context,
                        </tr>",
                        name = *myitem.name.as_ref().unwrap(),
                        stab_docs = stab_docs,
-                       docs = MarkdownSummaryLine(doc_value),
+                       docs = if cx.render_type == RenderType::Hoedown {
+                           format!("{}",
+                                   shorter(Some(&Markdown(doc_value,
+                                                          RenderType::Hoedown).to_string())))
+                       } else {
+                           format!("{}", MarkdownSummaryLine(doc_value))
+                       },
                        class = myitem.type_(),
                        stab = myitem.stability_class().unwrap_or("".to_string()),
                        unsafety_flag = unsafety_flag,
@@ -1915,7 +1926,9 @@ fn short_stability(item: &clean::Item, cx: &Context, show_reason: bool) -> Vec<S
             } else {
                 String::new()
             };
-            let text = format!("Deprecated{}{}", since, MarkdownHtml(&deprecated_reason));
+            let text = format!("Deprecated{}{}",
+                               since,
+                               MarkdownHtml(&deprecated_reason, cx.render_type));
             stability.push(format!("<div class='stab deprecated'>{}</div>", text))
         };
 
@@ -1944,7 +1957,8 @@ fn short_stability(item: &clean::Item, cx: &Context, show_reason: bool) -> Vec<S
                     let text = format!("<summary><span class=microscope>🔬</span> \
                                         This is a nightly-only experimental API. {}\
                                         </summary>{}",
-                                       unstable_extra, MarkdownHtml(&stab.unstable_reason));
+                                       unstable_extra,
+                                       MarkdownHtml(&stab.unstable_reason, cx.render_type));
                     stability.push(format!("<div class='stab unstable'><details>{}</details></div>",
                                    text));
                 }
@@ -1964,7 +1978,7 @@ fn short_stability(item: &clean::Item, cx: &Context, show_reason: bool) -> Vec<S
             String::new()
         };
 
-        let text = format!("Deprecated{}{}", since, MarkdownHtml(&note));
+        let text = format!("Deprecated{}{}", since, MarkdownHtml(&note, cx.render_type));
         stability.push(format!("<div class='stab deprecated'>{}</div>", text))
     }
 
@@ -2900,7 +2914,7 @@ fn render_impl(w: &mut fmt::Formatter, cx: &Context, i: &Impl, link: AssocItemLi
         write!(w, "</span>")?;
         write!(w, "</h3>\n")?;
         if let Some(ref dox) = i.impl_item.doc_value() {
-            write!(w, "<div class='docblock'>{}</div>", Markdown(dox))?;
+            write!(w, "<div class='docblock'>{}</div>", Markdown(dox, cx.render_type))?;
         }
     }
 
@@ -2999,11 +3013,11 @@ fn render_impl(w: &mut fmt::Formatter, cx: &Context, i: &Impl, link: AssocItemLi
                         // because impls can't have a stability.
                         document_stability(w, cx, it)?;
                         if get_doc_value(item).is_some() {
-                            document_full(w, item)?;
+                            document_full(w, item, cx.render_type)?;
                         } else {
                             // In case the item isn't documented,
                             // provide short documentation from the trait.
-                            document_short(w, it, link)?;
+                            document_short(w, it, link, cx.render_type)?;
                         }
                     }
                 } else {
@@ -3011,7 +3025,7 @@ fn render_impl(w: &mut fmt::Formatter, cx: &Context, i: &Impl, link: AssocItemLi
                 }
             } else {
                 document_stability(w, cx, item)?;
-                document_short(w, item, link)?;
+                document_short(w, item, link, cx.render_type)?;
             }
         }
         Ok(())
diff --git a/src/librustdoc/lib.rs b/src/librustdoc/lib.rs
index 0ca267bb82d..2a6134fde5c 100644
--- a/src/librustdoc/lib.rs
+++ b/src/librustdoc/lib.rs
@@ -93,6 +93,8 @@ pub mod test;
 
 use clean::AttributesExt;
 
+use html::markdown::RenderType;
+
 struct Output {
     krate: clean::Crate,
     renderinfo: html::render::RenderInfo,
@@ -169,6 +171,7 @@ pub fn opts() -> Vec<RustcOptGroup> {
                         "URL to send code snippets to, may be reset by --markdown-playground-url \
                          or `#![doc(html_playground_url=...)]`",
                         "URL")),
+        unstable(optflag("", "enable-commonmark", "to enable commonmark doc rendering/testing")),
     ]
 }
 
@@ -250,6 +253,12 @@ pub fn main_args(args: &[String]) -> isize {
     let css_file_extension = matches.opt_str("e").map(|s| PathBuf::from(&s));
     let cfgs = matches.opt_strs("cfg");
 
+    let render_type = if matches.opt_present("enable-commonmark") {
+        RenderType::Pulldown
+    } else {
+        RenderType::Hoedown
+    };
+
     if let Some(ref p) = css_file_extension {
         if !p.is_file() {
             writeln!(
@@ -273,15 +282,17 @@ pub fn main_args(args: &[String]) -> isize {
 
     match (should_test, markdown_input) {
         (true, true) => {
-            return markdown::test(input, cfgs, libs, externs, test_args, maybe_sysroot)
+            return markdown::test(input, cfgs, libs, externs, test_args, maybe_sysroot, render_type)
         }
         (true, false) => {
-            return test::run(input, cfgs, libs, externs, test_args, crate_name, maybe_sysroot)
+            return test::run(input, cfgs, libs, externs, test_args, crate_name, maybe_sysroot,
+                             render_type)
         }
         (false, true) => return markdown::render(input,
                                                  output.unwrap_or(PathBuf::from("doc")),
                                                  &matches, &external_html,
-                                                 !matches.opt_present("markdown-no-toc")),
+                                                 !matches.opt_present("markdown-no-toc"),
+                                                 render_type),
         (false, false) => {}
     }
 
@@ -295,7 +306,8 @@ pub fn main_args(args: &[String]) -> isize {
                                   output.unwrap_or(PathBuf::from("doc")),
                                   passes.into_iter().collect(),
                                   css_file_extension,
-                                  renderinfo)
+                                  renderinfo,
+                                  render_type)
                     .expect("failed to generate documentation");
                 0
             }
diff --git a/src/librustdoc/markdown.rs b/src/librustdoc/markdown.rs
index f75144c23ac..b9ed0eeaef7 100644
--- a/src/librustdoc/markdown.rs
+++ b/src/librustdoc/markdown.rs
@@ -26,6 +26,7 @@ use html::render::reset_ids;
 use html::escape::Escape;
 use html::markdown;
 use html::markdown::{Markdown, MarkdownWithToc, find_testable_code, old_find_testable_code};
+use html::markdown::RenderType;
 use test::{TestOptions, Collector};
 
 /// Separate any lines at the start of the file that begin with `# ` or `%`.
@@ -50,7 +51,8 @@ fn extract_leading_metadata<'a>(s: &'a str) -> (Vec<&'a str>, &'a str) {
 /// Render `input` (e.g. "foo.md") into an HTML file in `output`
 /// (e.g. output = "bar" => "bar/foo.html").
 pub fn render(input: &str, mut output: PathBuf, matches: &getopts::Matches,
-              external_html: &ExternalHtml, include_toc: bool) -> isize {
+              external_html: &ExternalHtml, include_toc: bool,
+              render_type: RenderType) -> isize {
     let input_p = Path::new(input);
     output.push(input_p.file_stem().unwrap());
     output.set_extension("html");
@@ -94,9 +96,9 @@ pub fn render(input: &str, mut output: PathBuf, matches: &getopts::Matches,
     reset_ids(false);
 
     let rendered = if include_toc {
-        format!("{}", MarkdownWithToc(text))
+        format!("{}", MarkdownWithToc(text, render_type))
     } else {
-        format!("{}", Markdown(text))
+        format!("{}", Markdown(text, render_type))
     };
 
     let err = write!(
@@ -147,7 +149,8 @@ pub fn render(input: &str, mut output: PathBuf, matches: &getopts::Matches,
 
 /// Run any tests/code examples in the markdown file `input`.
 pub fn test(input: &str, cfgs: Vec<String>, libs: SearchPaths, externs: Externs,
-            mut test_args: Vec<String>, maybe_sysroot: Option<PathBuf>) -> isize {
+            mut test_args: Vec<String>, maybe_sysroot: Option<PathBuf>,
+            render_type: RenderType) -> isize {
     let input_str = match load_string(input) {
         Ok(s) => s,
         Err(LoadStringError::ReadFail) => return 1,
@@ -158,7 +161,8 @@ pub fn test(input: &str, cfgs: Vec<String>, libs: SearchPaths, externs: Externs,
     opts.no_crate_inject = true;
     let mut collector = Collector::new(input.to_string(), cfgs, libs, externs,
                                        true, opts, maybe_sysroot, None,
-                                       Some(input.to_owned()));
+                                       Some(input.to_owned()),
+                                       render_type);
     old_find_testable_code(&input_str, &mut collector, DUMMY_SP);
     find_testable_code(&input_str, &mut collector, DUMMY_SP);
     test_args.insert(0, "rustdoctest".to_string());
diff --git a/src/librustdoc/test.rs b/src/librustdoc/test.rs
index 3206b502107..a30ec25de60 100644
--- a/src/librustdoc/test.rs
+++ b/src/librustdoc/test.rs
@@ -43,7 +43,7 @@ use errors;
 use errors::emitter::ColorConfig;
 
 use clean::Attributes;
-use html::markdown;
+use html::markdown::{self, RenderType};
 
 #[derive(Clone, Default)]
 pub struct TestOptions {
@@ -57,7 +57,8 @@ pub fn run(input: &str,
            externs: Externs,
            mut test_args: Vec<String>,
            crate_name: Option<String>,
-           maybe_sysroot: Option<PathBuf>)
+           maybe_sysroot: Option<PathBuf>,
+           render_type: RenderType)
            -> isize {
     let input_path = PathBuf::from(input);
     let input = config::Input::File(input_path.clone());
@@ -106,7 +107,8 @@ pub fn run(input: &str,
                                        opts,
                                        maybe_sysroot,
                                        Some(codemap),
-                                       None);
+                                       None,
+                                       render_type);
 
     {
         let dep_graph = DepGraph::new(false);
@@ -396,12 +398,15 @@ pub struct Collector {
     position: Span,
     codemap: Option<Rc<CodeMap>>,
     filename: Option<String>,
+    // to be removed when hoedown will be removed as well
+    pub render_type: RenderType,
 }
 
 impl Collector {
     pub fn new(cratename: String, cfgs: Vec<String>, libs: SearchPaths, externs: Externs,
                use_headers: bool, opts: TestOptions, maybe_sysroot: Option<PathBuf>,
-               codemap: Option<Rc<CodeMap>>, filename: Option<String>) -> Collector {
+               codemap: Option<Rc<CodeMap>>, filename: Option<String>,
+               render_type: RenderType) -> Collector {
         Collector {
             tests: Vec::new(),
             old_tests: HashMap::new(),
@@ -418,6 +423,7 @@ impl Collector {
             position: DUMMY_SP,
             codemap: codemap,
             filename: filename,
+            render_type: render_type,
         }
     }
 
@@ -458,20 +464,22 @@ impl Collector {
                     as_test_harness: bool, compile_fail: bool, error_codes: Vec<String>,
                     line: usize, filename: String) {
         let name = self.generate_name(line, &filename);
-        let name_beg = self.generate_name_beginning(&filename);
-        let mut found = false;
-        // to be removed when hoedown is removed
-        let test = test.trim().to_owned();
-        if let Some(entry) = self.old_tests.get_mut(&name_beg) {
-            found = entry.remove_item(&test).is_some();
-        }
-        if !found {
-            let _ = writeln!(&mut io::stderr(),
-                             "WARNING: {} Code block is not currently run as a test, but will in \
-                              future versions of rustdoc. Please ensure this code block is a \
-                              runnable test, or use the `ignore` directive.",
-                             name);
-            return
+        if self.render_type == RenderType::Pulldown {
+            let name_beg = self.generate_name_beginning(&filename);
+            let mut found = false;
+            // to be removed when hoedown is removed
+            let test = test.trim().to_owned();
+            if let Some(entry) = self.old_tests.get_mut(&name_beg) {
+                found = entry.remove_item(&test).is_some();
+            }
+            if !found {
+                let _ = writeln!(&mut io::stderr(),
+                                 "WARNING: {} Code block is not currently run as a test, but will in \
+                                  future versions of rustdoc. Please ensure this code block is a \
+                                  runnable test, or use the `ignore` directive.",
+                                 name);
+                return
+            }
         }
         let cfgs = self.cfgs.clone();
         let libs = self.libs.clone();
@@ -587,10 +595,15 @@ impl<'a, 'hir> HirCollector<'a, 'hir> {
         attrs.unindent_doc_comments();
         if let Some(doc) = attrs.doc_value() {
             self.collector.cnt = 0;
-            markdown::old_find_testable_code(doc, self.collector,
+            if self.collector.render_type == RenderType::Pulldown {
+                markdown::old_find_testable_code(doc, self.collector,
+                                                 attrs.span.unwrap_or(DUMMY_SP));
+                markdown::find_testable_code(doc, self.collector,
                                              attrs.span.unwrap_or(DUMMY_SP));
-            markdown::find_testable_code(doc, self.collector,
-                                         attrs.span.unwrap_or(DUMMY_SP));
+            } else {
+                markdown::old_find_testable_code(doc, self.collector,
+                                                 attrs.span.unwrap_or(DUMMY_SP));
+            }
         }
 
         nested(self);
diff --git a/src/test/rustdoc/check-hard-break.rs b/src/test/rustdoc/check-hard-break.rs
deleted file mode 100644
index f048b64d104..00000000000
--- a/src/test/rustdoc/check-hard-break.rs
+++ /dev/null
@@ -1,20 +0,0 @@
-// Copyright 2017 The Rust Project Developers. See the COPYRIGHT
-// file at the top-level directory of this distribution and at
-// http://rust-lang.org/COPYRIGHT.
-//
-// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
-// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
-// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
-// option. This file may not be copied, modified, or distributed
-// except according to those terms.
-
-#![crate_name = "foo"]
-
-// ignore-tidy-end-whitespace
-
-// @has foo/fn.f.html
-// @has - '<p>hard break:<br />'
-// @has - 'after hard break</p>'
-/// hard break:  
-/// after hard break
-pub fn f() {}
diff --git a/src/test/rustdoc/check-rule-image-footnote.rs b/src/test/rustdoc/check-rule-image-footnote.rs
deleted file mode 100644
index 46542677857..00000000000
--- a/src/test/rustdoc/check-rule-image-footnote.rs
+++ /dev/null
@@ -1,44 +0,0 @@
-// Copyright 2017 The Rust Project Developers. See the COPYRIGHT
-// file at the top-level directory of this distribution and at
-// http://rust-lang.org/COPYRIGHT.
-//
-// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
-// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
-// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
-// option. This file may not be copied, modified, or distributed
-// except according to those terms.
-
-#![crate_name = "foo"]
-
-// ignore-tidy-linelength
-
-// @has foo/fn.f.html
-// @has - '<p>markdown test</p>'
-// @has - '<p>this is a <a href="https://example.com" title="this is a title">link</a>.</p>'
-// @has - '<hr />'
-// @has - '<p>a footnote<sup id="supref1"><a href="#ref1">1</a></sup>.</p>'
-// @has - '<p>another footnote<sup id="supref2"><a href="#ref2">2</a></sup>.</p>'
-// @has - '<p><img src="https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png" alt="Rust" /></p>'
-// @has - '<div class="footnotes"><hr><ol><li id="ref1">'
-// @has - '<p>Thing&nbsp;<a href="#supref1" rev="footnote">↩</a></p></li><li id="ref2">'
-// @has - '<p>Another Thing&nbsp;<a href="#supref2" rev="footnote">↩</a></p></li></ol></div>'
-/// markdown test
-///
-/// this is a [link].
-///
-/// [link]: https://example.com "this is a title"
-///
-/// -----------
-///
-/// a footnote[^footnote].
-///
-/// another footnote[^footnotebis].
-///
-/// [^footnote]: Thing
-///
-///
-/// [^footnotebis]: Another Thing
-///
-///
-/// ![Rust](https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png)
-pub fn f() {}